The present invention relates to back constructions for seating for supporting the torso of seated users, and more specifically relates to back constructions adapted to facilitate manufacture while maintaining good aesthetics, low part count, optimized assembly, and low cost.
Recently, some seating manufacturers have designed xe2x80x9chigh-techxe2x80x9d looking chairs with backs including exposed frames and flexible back support structures. While this often eliminates covers and other xe2x80x9cextraxe2x80x9d pieces, it also can result in problems, because parts that usually are not finished and that include marks and rough edges caused by manufacturing are now visible or even emphasized. It can be expensive and costly to finish these parts. Further, parts that are structurally finished may fail visual inspection, causing some of the expensive parts to be thrown away as scrap.
In particular, the assignee of the present invention has designed an innovative and highly successful chair called the LEAP(trademark) chair (see U.S. Pat. No. 5,871,258, issued Feb. 16, 1999) that includes a very comfortable and flexible back shell assembly, and an arching back frame that extends from sides of its seat to a top of the back shell assembly for supporting the back shell assembly at top and bottom connections. Early designs of the LEAP(trademark) chair include a very comfortable and flexible back shell comprising a polymeric sheet (called herein a xe2x80x9cback shellxe2x80x9d). The early designs further include a metal xe2x80x9cbeltxe2x80x9d bracket that was insert molded into and extended along a bottom edge of the back shell. This construction worked well and was able to withstand the stresses associated with this design. However, the process of insert molding is expensive and non-repairable, and can generate significant scrap during manufacture. A less expensive alternative is desired that facilitates manufacture, permits repair, and yet that maintains the good appearance of the chair.
The LEAP(trademark) chair includes top connections that connect a top of its flexible back shell assembly to the back frame. These top connections are in a high visibility area. Further, many consumers like to see the flexible back shell, and often they prefer not to have any cushion or fabric covering. However, this results in the top connection being even more visible. Specifically, the problem is that the top connections must be very secure, yet permit easy assembly and also look clean and be aesthetically acceptable. Preferably, the connections should not include any visible screws or the like. Also, the top connections in the LEAP(trademark) chair must permit some flexing and movement at the top connections, without binding the polymeric material of the back shell. Otherwise, concentrated stresses in the back shell, which occur when the back shell is flexed to an extreme position, can stress the polymeric material to such an extent that visible white stress marks can occur at the high stress areas. This problem became noticed in the early designs of the LEAP(trademark) chair when the back shell was not covered with an upholstered cushion, and when the back shell was flexed to a maximum bent condition. The white stress locations showed on a face of the back shell, which a person sees as they approach and sit down in the chair.
An improved back frame for the LEAP(trademark) chair is also desired. The physics of manufacturing the arching back frame make it preferable to mold the part with material flowing into opposing and balanced halves of the mold cavity from a center location through what is known as a molding gate. A problem is that the high material flow and shearing forces at the molding gate can cause part defects and surface blemishes in the back frame at the molding gate. Further, sharp edges and protrusions can occur at the molding gate where the xe2x80x9crunnerxe2x80x9d (i.e. the material that flows toward but that does not enter the molding gate) and the part material just inside the molding gate are separated at an end of the molding process. Thus, the molding process requires extra effort to trim and smooth over these areas of the xe2x80x9crawxe2x80x9d molded back frame. These blemishes and jagged edges would normally not be seen since, in most chairs, they are covered by upholstery or cushion material. However, as noted above, the present LEAP(trademark) back frame is not covered.
Accordingly, a back construction solving the aforementioned difficulties and problems, and having the aforementioned advantages is desired.
In one aspect of the present invention, a back construction for seating includes a structural back frame having an elongated section with a visible area where a blemish or other visible defect is undesirable, and an aesthetic cover engaging opposing surfaces on the elongated section and that is shaped to aesthetically cover the visible area.
In another aspect, a back construction for seating includes a back frame, a back shell, and a connection connecting the back shell to the back frame. The connection includes internal connecting structure on the back shell and the back frame that securely engage to hold the back shell to the back frame. The connection further includes an external retainer housing surrounding the internal connecting structure, the external retainer housing including a tubular sleeve that provides an aesthetic appearance around the internal connecting structure.
In another aspect, a back construction includes a back support having sides and a bottom edge and a channel defined along the bottom edge. An elongated bracket is provided having a center section shaped to fit into the channel. The bracket is retained in the channel and has end sections that extend forwardly from the sides of the back support. The end sections are adapted to pivotally engage a back frame structure.
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.